JP2001053336A - Iii nitride compound semiconductor light emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-chip white LED coping with full color range which can be manufacture by relatively inexpensive production facilities and whose color reproducibility range is sufficiently, when it is used as an illuminator. SOLUTION: On an intermediate layer 104, an MQW active layer 160, of about 500 Å thickness is formed of a total of five semiconductor layers. This MQW active layer 160 constitutes a MQW structure, with a total of two barrier layers 162 consisting of GaN of about 100 Å thickness and a total of three well layers differing in wavelength of light emission laminated alternately. These three well layers are laminated in the order of a red light-emitting well layer 161R, consisting of Al0.1In0.9N of about 20 Å thickness where impurities (Zn, Si) are added, a green light-emitting well layer 161G with no addition of impurities consisting of Ga0.8In0.2N of about 50 Å thickness, and a blue light-emitting well layer 161B with addition of impurities consisting of Ga0.95In0.05 N of about 30 Å thickness. According to the illumination of this white LED, red can be seen, which cannot be seen with a one-chip white LED.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white light-emitting group III nitride compound semiconductor light emitting device having a wide color reproduction range.

[0002]

2. Description of the Related Art As a white light emitting LED (a group III nitride compound semiconductor light emitting device), "Isao Akasaki:" Attraction of Blue Light Emitting Devices ", Kbooks series 122, Industrial Research Institute, Ltd., 1997.5.1" ( (Hereinafter referred to as "Cited Document 1"), or the published patent publication "JP-A-5-1
52609: Light-Emitting Diode ”(hereinafter referred to as“ Cited Document 2 ”) and the like are generally widely known.

FIG. 4 is a cross-sectional view of a white light emitting semiconductor light emitting device 400 disclosed in the above cited document 1. The present semiconductor light emitting device 4
Reference numeral 00 denotes a YAG-based phosphor that converts blue light into yellow light placed around a blue-emitting group III nitride compound semiconductor light-emitting element (diode chip) mounted in a metal cup. is there.

FIG. 5 is a graph showing an emission spectrum of the semiconductor light emitting device 400. The light obtained directly from the chip shows a sharp peak around 450 nm, and the light from the phosphor shows a broad spectrum with a peak around 550 nm. This white LED (semiconductor light emitting element 40
In the case of 0), the chromaticity of the emission color can be changed by adjusting the amount of the phosphor used and the chemical composition ratio.

FIG. 6 is a chromaticity diagram showing the color reproduction range of the semiconductor light emitting device 400. By adjusting the amount and chemical composition ratio of the phosphor used in this way, it is possible to realize an LED that emits an arbitrary color inside the sector at the center of the chromaticity diagram.

Further, in the “3 in 1 full color LED” of white light emission described in the above cited document 1, a semiconductor light emitting element made of GaAlAs is used as a red light emitting LED chip.

[0007]

For example, as shown in FIG. 6, according to the conventional semiconductor light emitting device 400, the color reproduction range is not sufficiently wide. And red was not seen. As described above, conventionally, a full-color compatible illumination having a sufficiently wide color reproduction range is used.
It has not been easy to realize the semiconductor light emitting device of a chip.

Further, the above-mentioned “3 in 1 full color LED”
However, there is a problem in that the number of chips for obtaining white color increases, which complicates the manufacturing process, takes a long time to manufacture, and increases the production cost.

Further, the above-mentioned “3 in 1 full color LED”
In conventional semiconductor light emitting devices such as, for example, arsenic (As) is embedded in a red light emitting semiconductor layer in order to realize a red light emitting chip.
Was used. However, when mass-producing a product using an arsenic (As) compound or the like, it is necessary to pay particular attention to the ecosystem and the environment, and there has been a problem in terms of capital investment and productivity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to use a relatively inexpensive production method that does not use an arsenic (As) compound or the like and therefore does not require special consideration. An object of the present invention is to provide a full-color one-chip white LED that can be manufactured by equipment and has a sufficiently wide color reproduction range.

[0011]

In order to solve the above-mentioned problems, the following means are effective. That is, the first means has a quantum well structure (Al _x Ga _{1 -x} ) _y In _{1 -y} N (0
.Ltoreq.x.ltoreq.1; 0.ltoreq.y.ltoreq.1) In a semiconductor light emitting device in which semiconductor layers formed of a group III nitride compound are stacked, at least three or more well layers out of a plurality of well layers are used. The mixed crystal ratios are different from each other, and an acceptor impurity and a donor impurity are added to at least one well layer to form a well layer, and the chromaticity of each light emitted from at least three or more well layers is different from each other. In this case, the combined light emitted from the light extraction surface based on the light emission of all the well layers is converted to white light.

Each of the well layers may be a well layer having a single quantum well structure or a well layer having a multiple quantum well structure. Further, each of the well layers described above may include a barrier layer with a smaller thickness in the well layer. In addition, the respective well layers may mutually interfere with each other or may not mutually interfere with each other.

The second means is the first means, wherein the mixed crystal ratio of the red light emitting well layer is Al _y In _1-y N (0 ≦ 0).
y ≦ 0.1).

Further, the third means may be the first or the second means.
In _1-y Ga _y to which no impurity is added
A blue light emitting well layer and a green light emitting well layer formed of N (0.7 ≦ y <1). However, the blue light emitting well layer may be a well layer that emits blue-violet (380 nm to 455 nm) light whose emission wavelength is slightly shorter than blue (455 nm to 485 nm).

Further, the fourth means includes the first to third means.
The concentration of the acceptor impurity and the concentration of the donor impurity are 1 × 10 ¹⁷ / cm ³ or more and 1 × 10 ¹⁷ / cm ³ or more, respectively.
It is to be 10 ²¹ / cm ³ or less.

The fifth means includes the first to fourth means.
In any one of means, zinc (Zn), beryllium (Be), calcium (Ca), strontium (Sr), barium (B
a) or using magnesium (Mg).

Further, the sixth means comprises the first to fifth means.
In any one of the means, carbon (C), silicon (Si), tin (Sn), sulfur (S), selenium
(Se) or tellurium (Te).

Further, the seventh means includes the first to sixth means.
In any one of the means, the well layers are stacked in order of decreasing emission wavelength as approaching the light extraction surface.

Further, the eighth means includes the first to seventh means.
In any one of the means, light is emitted from the well layer by adjusting the thickness of each well layer, the mixed crystal ratio, the type of the added impurity, the concentration of the added impurity, or the number of layers for each emission wavelength. The weighted average coordinates of the chromaticity coordinates on the chromaticity diagram of each light according to the lightness are configured to substantially match the white point coordinates (1/3, 1/3). With the above means, the above-mentioned problem can be solved.

[0020]

According to the means of the present invention, since a red light emitting well layer and two or more well layers emitting light other than red light are formed, the chromaticity of at least three or more well layers is determined. Are emitted. Therefore, when the white LED of the present invention is used as illumination, the conventional one-chip white LED L
The red color that could not be seen with the ED illumination becomes visible.

[0021] In this case, the chromaticity coordinates of the combined light emitted from the light output surface (x, y), respectively chromaticity coordinates and brightness of light emitted from each well layer (x _i, y _i), if M _i, between these values, the following relationship holds.

[Number 1] ^{_{(i = 1 Σ N M i}} ) (x, y) = i = 1 Σ N {M i (x i, y i)} ... (1) However, where, N is the total well layer Number of layers.

Here, the mixed crystal ratio of each well layer, the type of the added impurity, and the concentration of the added impurity can be parameters for determining the emission wavelength of each well layer, and the film thickness of each well layer and each light emission. The number of layers for each wavelength can be a parameter for determining the emission intensity (brightness) for each emission wavelength. Therefore, if the various parameters described above are adjusted optimally for each well layer, the chromaticity coordinate point (x _i , y _i ) of the light emitted from each well layer becomes a vertex on the chromaticity diagram. , It is possible to reproduce all the arbitrary colors located inside the polygon by combining these lights.

For example, when the above-mentioned polygon (thus, a triangle) is constituted by a total of three well layers, all the well layers are composed of the red light emitting well layer, the green light emitting well layer, and the blue light emitting well layer. With this configuration, the widest range of colors can be reproduced (FIG. 3). However, the blue light emitting well layer may be a well layer that emits blue-violet (380 nm to 455 nm) light whose emission wavelength is slightly shorter than blue (455 nm to 485 nm).

Accordingly, in particular, the above polygons are extensively drawn on the chromaticity diagram, and the weighted average coordinates of the light emitted from all the well layers by the brightness of the chromaticity coordinates on the chromaticity diagram are represented by white point coordinates (1). / 3,1 / 3), the light synthesizing function shown in equation (1) enables a full-color 1-chip white color with a sufficiently wide color reproduction range when used for white illumination or the like. L
ED can be realized.

Also, if the well layers are stacked in order of decreasing emission wavelength as approaching the light extraction surface, light emitted from each well layer is absorbed by the well layer existing on the light extraction surface side. As a result, the light extraction efficiency is increased, and the controllability of chromaticity is improved.

Furthermore, according to the means of the present invention, the product (III
An arsenic (As) compound or the like need not be used in the group nitride semiconductor light emitting device) and the manufacturing process. For this reason,
A white LED can be manufactured by relatively inexpensive production equipment that does not require special consideration. By these actions and effects, the above-mentioned problem can be solved and the object of the present invention can be achieved.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on specific embodiments. FIG. 1 is a cross-sectional view of a wire bonding type semiconductor light emitting device 100 according to the present invention.
Aluminum nitride (AlN) on the sapphire substrate 101
A buffer layer 102 having a thickness of about 200 ° is formed, and a silicon (Si) -doped GaN film is formed thereon.
A 4.0 μm n-type contact layer 103 is formed.

On the n-type contact layer 103, an intermediate layer 104 made of non-doped In _0.03 Ga _0.97 N and having a thickness of about 2000 ° is formed.

The intermediate layer 104 has a thickness of about 2
An n-type cladding layer 105 of GaN having a thickness of 50 ° is formed, and an MQW active layer 160 having a thickness of about 300 ° is formed by a total of five semiconductor layers thereon. The MQW active layer 160 has an MQW structure by alternately stacking a total of four barrier layers 162 made of GaN having a thickness of about 100 ° and a total of three well layers having different emission wavelengths. I have.

The three well layers are composed of a red light emitting well layer 161R made of Al _0.1 In _0.9 N having a thickness of about 20 ° to which impurities (Zn, Si) are added, and an In _0.2 Ga _0.8 N film having a thickness of about 50 °. Green light-emitting well layer 161G having a thickness of about 30
The blue light-emitting well layers 161B made of In _0.05 Ga _0.95 N and not doped with impurities are stacked in this order via the barrier layer 162.

On this MQW active layer 160, a GaN cap layer 107 having a thickness of about 100 ° is formed, and a p-type cladding layer 108 made of p-type Al _0.12 Ga _0.88 N having a thickness of about 200 ° is formed thereon. Further, on the p-type cladding layer 108, a film thickness of about 6 of p-type Al _0.05 Ga _0.95 N is formed.
A p-type contact layer 109 of 00 ° is formed.

A translucent thin-film positive electrode 110 is formed on the p-type contact layer 109 by metal evaporation, and a negative electrode 140 is formed on the n-type contact layer 103. The translucent thin-film positive electrode 110 has a thin-film first positive electrode layer 111 made of cobalt (Co) with a thickness of about 15 ° bonded to the p-type contact layer 109, and a gold (Au) film with a thickness of about 60 ° bonded to Co. And the second thin-film positive electrode layer 112.

The thick-film positive electrode 120 includes a thick-film positive electrode first layer 121 of about 175 ° in thickness of vanadium (V) and a thick-film positive electrode second layer of about 15000 ° in thickness of gold (Au).
Layer 122 and a third layer 123 of thick positive electrode made of aluminum (Al) having a thickness of about 100 °
It is configured by sequentially laminating the layers 10 on top.

The negative electrode 140 having a multilayer structure has a film thickness of about 17 from the exposed portion of the n-type contact layer 103.
5% vanadium (V) layer 141, aluminum (Al) layer 142 having a thickness of about 1000 mm, vanadium (V) layer 143 having a thickness of about 500 mm, and nickel (Ni) having a thickness of about 5000 mm
It is constituted by sequentially laminating a layer 144 and a gold (Au) layer 145 having a thickness of 8000 °.

A protective film 130 made of a SiO ₂ film is formed on the uppermost part.
The lowermost part on the opposite side, which corresponds to the bottom surface of No. 01, has a thickness of about 500
Reflective metal layer 150 made of 0 ° aluminum (Al)
Is formed by metal evaporation. The reflective metal layer 150 is made of a metal such as Rh, Ti, W, etc., as well as TiN, H
A nitride such as fN may be used.

Next, a method for manufacturing the light emitting device 100 will be described. The light emitting device 100 was manufactured by vapor phase growth using metal organic chemical vapor deposition (MOVPE). The gases used were ammonia (NH ₃ ), carrier gas (H ₂ , N ₂ ), trimethylgallium (Ga (CH ₃ ) ₃ ) (hereinafter “TM
G ”), trimethylaluminum (Al (CH ₃ ) ₃ ) (hereinafter referred to as“ TMA ”), trimethylindium (In (CH ₃ ) ₃ )
(Hereinafter referred to as "TMI"), a silane (SiH ₄₎ and cyclopentadienyl magnesium _{(Mg (C 5 H 5)} 2) ( hereinafter referred to as "CP ₂ Mg"). First, a single-crystal sapphire substrate 101 whose main surface is the a-plane cleaned by organic cleaning is mounted on a susceptor placed in a reaction chamber of a MOVPE apparatus. Next, at normal pressure
The substrate 101 was baked at a temperature of 1150 ° C. while flowing H ₂ into the reaction chamber. Next, the temperature of the substrate 101 was lowered to 400 ° C., and H ₂ , NH ₃ and TMA were supplied to form the AlN buffer layer 102 to a thickness of about 200 °.

Next, the temperature of the substrate 101 is raised to 1150 ° C., H ₂ , NH ₃ , TMG and silane are supplied, and the film thickness is reduced to about 4.
An n-type contact layer 103 made of GaN doped with silicon (Si) having a thickness of 0 μm and an electron concentration of 2 × 10 ¹⁸ / cm ³ was formed.
Next, the temperature of the substrate 11 is set to 850 ° C., and N ₂ or H ₂ , N
By supplying H ₃ , TMG and TMI, In 2000
_An intermediate layer 104 made of _0.03 Ga _0.97 N was formed.

After forming the intermediate layer 104, the substrate 1
01 at 850 ° C., N ₂ or H ₂ , NH ₃ , TM
G was supplied to form an n-type cladding layer 105 of GaN with a thickness of about 250 °. Then, N ₂ or H _2, NH _3, TMA
, TMI, DEZ and silane to add zinc (Zn) and silicon (Si) as acceptor impurities at a concentration of 2 × 10 ¹⁷ / cm ³ and donor impurities at a concentration of 3 × 10 ¹⁷ / cm ^{3 respectively} A red light emitting well layer 161R made of Al _0.1 In _0.9 N with a thickness of about 20 ° was formed.

Next, N_TwoOr H_Two, NH_Three, Supply TMG,
A barrier layer 162 made of GaN having a thickness of about 100 ° is formed.
Was. Then N_TwoOr H_Two, NH_Three, TMG and TMI
And the film thickness of about 50 °_0.2Ga _0.8N-free
An additional green light emitting well layer 161G was formed.

Next, N_TwoOr H_Two, NH_Three, Supply TMG,
A barrier layer 162 made of GaN having a thickness of about 100 ° is formed.
Was. Then N_TwoOr H_Two, NH_Three, TMG and TMI
And the thickness of about 30mm In_0.05Ga _0.95N-free
An additional blue light emitting well layer 161B was formed. Like this
And an MQW of about 300.degree.
An active layer 160 was formed.

Next, N ₂ or H ₂ , NH ₃ , and TMG are supplied.
A cap layer 107 made of GaN having a thickness of about 100 ° was formed.

Next, the temperature of the substrate 11 is set to 1150 ° C._Twoor
Is H_Two, NH_Three, TMG, TMA and CP_TwoSupply Mg, film thickness about
200 °, p-type Al doped with magnesium (Mg)_0.12Ga
_0.88A p-type cladding layer 108 of N 2 was formed. Next
And the temperature of the substrate 11 is maintained at 1100 ° C._TwoOr H_Two, N
H_Three, TMG, TMA and CP _TwoBy supplying Mg, the film thickness is about 600
Ｐ, p-type Al doped with magnesium (Mg)_0.05Ga _0.95N
A p-type contact layer 109 made of was formed.

Next, an etching mask is formed on the p-type contact layer 109, and the mask in a predetermined region is removed.
P-type contact layer 10 not covered by mask
9, p-type cladding layer 108, cap layer 107, MQW
Active layer 160, n-type cladding layer 105, intermediate layer 104,
A part of the n-type contact layer 103 was etched by reactive ion etching using a gas containing chlorine to expose the surface of the n-type contact layer 103. Next, in the following procedure, the negative electrode 140 bonded to the n-type contact layer 103 is formed.
And a translucent thin film positive electrode 110 bonded to the p-type contact layer 109.

(1) After evacuating to a high vacuum of the order of 10 ⁻⁴ Pa or less using a vapor deposition apparatus, a Co film having a thickness of about 15 ° is uniformly formed on the surface, and a thin film positive electrode formed of this Co is formed. On the first layer 111, a thin-film positive electrode second layer 112 of Au having a thickness of about 60 ° is formed. (2) Next, apply photoresist uniformly on the surface,
By photolithography, the photoresist laminated on the p-type contact layer 109 except for the portion where the light-transmitting thin-film positive electrode 110 is formed is removed.

(3) Next, exposed by etching
After removing Co and Au, the photoresist is removed, and a translucent thin film positive electrode 110 is formed on the p-type contact layer 109. (4) Next, a photoresist is applied, a window is formed in a predetermined region on the exposed surface of the n-type contact layer 103 by photolithography, and the window is evacuated to a high vacuum of the order of 10 ⁻⁴ Pa or less. A vanadium (V) layer 141 having a thickness of about 175 ° and an aluminum (Al) layer 142 having a thickness of about 1.8 μm were sequentially deposited. Next, the photoresist is removed. Thus, a negative electrode 140 is formed on the exposed surface of the n-type contact layer 103. On top of the light-transmitting thin-film positive electrode 110 formed by the above steps, a photoresist is evenly applied to form a thick-film positive electrode 120 to form a thick-film positive electrode 12.
A window is opened in the photoresist at the portion where 0 is formed. afterwards,
A vanadium (V) layer 121 having a thickness of about 175 °, a gold (Au) layer 122 having a thickness of about 15000 °, and a thickness of about 100 °
The aluminum (Al) layer 123 is sequentially formed on the translucent thin-film positive electrode 110 by vapor deposition, and the thick-film positive electrode 120 is formed by the lift-off method as in the process (4).

(5) Thereafter, the n-type contact layer and the negative electrode 1
40, and heat treatment (sintering) for reducing the contact resistance between the p-type contact layer 109 and the translucent thin film positive electrode 110 was performed. That is, the sample atmosphere was evacuated by a vacuum pump, and O ₂ gas was supplied to a pressure of 10 Pa.
In that state, the temperature of the atmosphere was set to about 570 ° C., and the heating was performed for about 4 minutes.

Thereafter, a protective film 130 made of SiO ₂ is uniformly formed on the uppermost layer exposed at the upper portion by vapor deposition, and a thick film positive electrode 120 and a negative electrode 120 are formed through a photoresist coating and a photolithography process. Windows having substantially the same area were formed by wet etching one by one so that an externally exposed portion was formed at 140. On the back surface of the sapphire substrate, a Rh reflection film was formed by vapor deposition.

Thus, the semiconductor light emitting device 100 shown in FIG. 1 was formed. FIG. 2 shows the present semiconductor light emitting device 10.
4 shows a graph of an emission spectrum of 0. According to this graph, light emitted from the red light emitting well layer 161R has a sharp peak near 460 nm, light emitted from the green light emitting well layer 161G has a sharp peak near 530 nm, and light emitted from the blue light emitting well layer 161B. It can be seen that this light has a sharp peak near 650 nm.

FIG. 3 is a chromaticity diagram showing the color reproduction range of the semiconductor light emitting device 100. Symbols R, G, and B in the figure represent chromaticity near the peak value of each light. By appropriately setting the thickness of each of the well layers 161R, 161G, and 161B, in the semiconductor light emitting device 100, the weighted average coordinates (x, y) based on the brightness of the chromaticity coordinates shown in Expression (1) Are substantially coincident with the coordinates (1/3, 1/3) of the white point W.

Thus, a one-chip white L corresponding to a full color having a sufficiently wide color reproduction range when used for white illumination or the like.
ED was realized. That is, if the present semiconductor light emitting device 100 is used as illumination, an arbitrary color inside the triangle at the center of the chromaticity diagram can be reproduced by this illumination.

According to the semiconductor light emitting device 100,
Since ultraviolet light and infrared light are not emitted, energy efficiency is high and eye-friendly illumination can be realized with one chip.

In the above embodiment, a one-chip white LED of a wire bonding type has been described, but the present invention can be applied to an arbitrary type of one-chip white LED such as a flip chip type.

For example, in the case of the flip-chip type, a plurality of well layers are stacked in the reverse order of the above-described embodiment. As a result, even in the case of the flip-chip type, the well layers can be stacked in the order of decreasing emission wavelength as approaching the light extraction surface, so that light emitted from each well layer is absorbed by the well layer existing on the light extraction surface side. Light absorption effect is prevented. Therefore, as in the above embodiment, a full-color one-chip white LED having high light extraction efficiency and a sufficiently wide color reproduction range can be obtained.

In the case of the flip-chip type, the reflective metal layer 150 is unnecessary, and instead of the translucent thin-film positive electrode 110, a film made of a metal having good reflectivity such as rhodium (Rh) is used. A non-light-transmitting thick film electrode of about 2000 ° is formed. In this case, the thick film positive electrode 120 is unnecessary.

In the above embodiment, the well layer has a total of three layers of red light emission, green light emission, and blue light emission. However, a well layer of yellow light emission or blue light emission may be further provided. By increasing the number of well layers having different emission wavelengths as shown in FIG.
Can be changed to a wider range of polygons, so a full-color compatible one that can reproduce a wider range of chromaticity
A chip white LED can be realized.

In the above embodiment, the brightness of the light for each emission wavelength is adjusted by the thickness of each well layer. However, the brightness of the light for each emission wavelength is adjusted for the layer of the well layer for each emission wavelength. It may be adjusted by the number.

In the above embodiment, the MQW active layer 16
Although 0 is the active layer, the active layer may be composed of a plurality of single quantum wells. That is, each well layer in the present invention may be a well layer having a single quantum well structure or a well layer having a multiple quantum well structure. Further, each well layer of the present invention may include a thinner barrier layer in the well layer. In addition, the respective well layers of the present invention may mutually interfere with each other or may not mutually interfere with each other. The present invention can be applied to a semiconductor light emitting device having any of these quantum well structures.

The amount of zinc and silicon added is 1 ×
Light emission due to transition between impurity levels can be obtained at about 10 ¹⁷ to 1 × 10 ²¹ / cm ³ . A group II element or a group IV element other than zinc can be used as the acceptor impurity element, and a group IV element or a group VI element other than silicon can be used as the donor impurity element. Note that, in the present invention, the non-added layer refers to a layer to which an impurity is not intentionally added at the time of formation.

In the above embodiment, a sapphire substrate was used. However, in addition to sapphire, Si,
SiC, GaN, MgAl ₂ O ₄ or the like can be used. Although AlN is used for the buffer layer, AlGaN, GaN, InAlGaN, or the like can be used.

The MQW active layer 1 in the above embodiment is
Although a GaN layer was used for the barrier layer 60, the barrier layer was not limited to the GaN layer, but had a larger energy band gap than the well layer, for example, an AlGaN layer, an AlN layer.
Layer, an AlInN layer, an InAlGaN layer, or the like can be used.

[Brief description of the drawings]

FIG. 1 is a sectional view of a white light emitting semiconductor light emitting device 100 according to an embodiment of the present invention.

FIG. 2 is a graph showing an emission spectrum of the semiconductor light emitting device 100.

FIG. 3 is a chromaticity diagram showing a color reproduction range of the semiconductor light emitting device 100.

FIG. 4 shows a white light emitting semiconductor light emitting device 40 according to the prior art.
FIG.

FIG. 5 is a graph showing an emission spectrum of the semiconductor light emitting element 400.

FIG. 6 is a chromaticity diagram showing a color reproduction range of the semiconductor light emitting element 400.

[Explanation of symbols]

100, 400: semiconductor light emitting element 101: sapphire substrate 102: buffer layer 103: high carrier concentration n ⁺ layer 104: intermediate layer 105: n-type cladding layer 160: MQW active layer 161B: blue light emitting well layer 161G: green light emitting well layer 161R red emission well layer 162 barrier layer 107 cap layer 108 p-type cladding layer 109 p-type contact layer 120 positive electrode 121 first metal layer 122 second metal layer 123 third metal layer 130 Protective film 140: negative electrode W: white point B: blue light emitting point G: green light emitting point R: red light emitting point

Claims (8)

[Claims] (Al _x Ga _{1 -x} ) _y having a quantum well structure
In a semiconductor light emitting device in which a semiconductor layer formed of a group III nitride compound composed of In _1-y N (0 ≦ x ≦ 1; 0 ≦ y ≦ 1) is laminated, at least three of the plurality of well layers are formed. At least one well layer is formed by adding an acceptor impurity and a donor impurity to each other so that the mixed crystal ratios of the at least three well layers are different from each other. A group III nitride-based compound semiconductor light emitting device characterized in that, by making light chromaticities different from each other, synthetic light emitted from a light extraction surface based on light emission of all well layers is white light. 2. The group III nitride compound semiconductor according to claim 1, wherein the mixed crystal ratio of the red light emitting well layer is Al _y In _1-y N (0 ≦ y ≦ 0.1). Light emitting element. 3. In _1-y Ga _y N to which impurities are not added
3. The group III nitride compound semiconductor light emitting device according to claim 1, further comprising a blue light emitting well layer and a green light emitting well layer formed of (0.7 ≦ y <1). 4. The method according to claim 1, wherein the concentrations of the acceptor impurity and the donor impurity are respectively 1 × 10 ¹⁷ / cm ³ or more and 1 × 10 ²¹ / cm ³ or less. Or 1
Item 13. The group III nitride compound semiconductor light-emitting device according to item 9. 5. The acceptor impurities include zinc (Zn), beryllium (Be), and calcium (C
The group III nitride compound semiconductor light emitting device according to any one of claims 1 to 4, wherein the light emitting device is a), strontium (Sr), barium (Ba), or magnesium (Mg). 6. The method according to claim 1, wherein the donor impurity is carbon (C), silicon (Si), tin (Sn), sulfur (S), selenium (Se), or tellurium (Te). A group III nitride compound semiconductor light-emitting device according to claim 1. 7. The group III nitride according to claim 1, wherein the well layers are stacked in order of decreasing emission wavelength as approaching the light extraction surface. Compound semiconductor light emitting device. 8. The weighted average coordinates of the chromaticity coordinates of each light emitted from the well layer on the chromaticity diagram according to lightness are: the film thickness of each of the well layers, the mixed crystal ratio, the type of added impurities, 4. The method according to claim 1, wherein the white point coordinates (1/3, 1/3) substantially coincide with each other by adjusting the impurity concentration or the number of layers for each emission wavelength. Any one of claims 7
Item 13. The group III nitride compound semiconductor light-emitting device according to item 9.